cocos3——11.事件分发

【纹理】
TextureCache::addImage
texture = new (std::nothrow) Texture2D(); // ref = 1, 没有autorelease


TextureCache::removeUnusedTextures
把引用计数是1的纹理释放掉
TextureCache::removeAllTextures
释放所有缓存的纹理


【事件】
分发顺序：优先级<0，场景图顺序（从前往后）（优先级=0），优先级>0


注册订阅者：
用场景图优先级方式添加，要绑定node，默认优先级为0
void addEventListenerWithSceneGraphPriority(EventListener* listener, Node* node);
按固定优先级方式添加，不能设置优先级为0（因为0在上面用，有特殊意义）
void addEventListenerWithFixedPriority(EventListener* listener, int fixedPriority);


添加的时候是放到一个map去：
std::unordered_map<EventListener::ListenerID, EventListenerVector*> _listenerMap;

而侦听id根据不同的事件类型获取的，每种事件对应一个字符串，而用户自定义事件则是事件的名字：

static EventListener::ListenerID __getListenerID(Event* event){    EventListener::ListenerID ret;    switch (event->getType())    {        case Event::Type::ACCELERATION:            ret = EventListenerAcceleration::LISTENER_ID;            break;        case Event::Type::CUSTOM:            {                auto customEvent = static_cast<EventCustom*>(event);                ret = customEvent->getEventName();            }            break;        case Event::Type::KEYBOARD:            ret = EventListenerKeyboard::LISTENER_ID;            break;        case Event::Type::MOUSE:            ret = EventListenerMouse::LISTENER_ID;            break;        case Event::Type::FOCUS:            ret = EventListenerFocus::LISTENER_ID;            break;        case Event::Type::TOUCH:            // Touch listener is very special, it contains two kinds of listeners, EventListenerTouchOneByOne and EventListenerTouchAllAtOnce.            // return UNKNOWN instead.            CCASSERT(false, "Don't call this method if the event is for touch.");            break;#if (CC_TARGET_PLATFORM == CC_PLATFORM_ANDROID || CC_TARGET_PLATFORM == CC_PLATFORM_IOS)        case Event::Type::GAME_CONTROLLER:            ret = EventListenerController::LISTENER_ID;            break;#endif        default:            CCASSERT(false, "Invalid type!");            break;    }        return ret;}

暂停、恢复与节点相关的侦听
void resumeEventListenersForTarget(Node* target, bool recursive = false);
void pauseEventListenersForTarget(Node* target, bool recursive = false);


开关订阅者
inline void setEnabled(bool enabled)
inline bool isEnabled()


设置优先级
void setPriority(EventListener* listener, int fixedPriority);


分发事件：
void dispatchEvent(Event* event);
void dispatchCustomEvent(const std::string &eventName, void *optionalUserData = nullptr);

void EventDispatcher::dispatchEvent(Event* event){    if (!_isEnabled)        return;        updateDirtyFlagForSceneGraph();            DispatchGuard guard(_inDispatch);        if (event->getType() == Event::Type::TOUCH)    {        dispatchTouchEvent(static_cast<EventTouch*>(event));        return;    }        auto listenerID = __getListenerID(event);        sortEventListeners(listenerID);        auto iter = _listenerMap.find(listenerID);    if (iter != _listenerMap.end())    {        auto listeners = iter->second;                auto onEvent = [&event](EventListener* listener) -> bool{            event->setCurrentTarget(listener->getAssociatedNode());            listener->_onEvent(event);            return event->isStopped();        };                dispatchEventToListeners(listeners, onEvent);    }        updateListeners(event);}

  分发的过程：先对标记为dirty的侦听者进行排序，然后根据事件的侦听id找到对应的侦听者集合，然后遍历处理。而处理的结果event->isStopped会影响该事件是否继续传递给其他侦听者。

void EventDispatcher::dispatchEventToListeners(EventListenerVector* listeners, const std::function<bool(EventListener*)>& onEvent){    bool shouldStopPropagation = false;    auto fixedPriorityListeners = listeners->getFixedPriorityListeners();    auto sceneGraphPriorityListeners = listeners->getSceneGraphPriorityListeners();        ssize_t i = 0;    // priority < 0    if (fixedPriorityListeners)    {        CCASSERT(listeners->getGt0Index() <= static_cast<ssize_t>(fixedPriorityListeners->size()), "Out of range exception!");                if (!fixedPriorityListeners->empty())        {            for (; i < listeners->getGt0Index(); ++i)            {                auto l = fixedPriorityListeners->at(i);                if (l->isEnabled() && !l->isPaused() && l->isRegistered() && onEvent(l))                {                    shouldStopPropagation = true;                    break;                }            }        }    }        if (sceneGraphPriorityListeners)    {        if (!shouldStopPropagation)        {            // priority == 0, scene graph priority            for (auto& l : *sceneGraphPriorityListeners)            {                if (l->isEnabled() && !l->isPaused() && l->isRegistered() && onEvent(l))                {                    shouldStopPropagation = true;                    break;                }            }        }    }    if (fixedPriorityListeners)    {        if (!shouldStopPropagation)        {            // priority > 0            ssize_t size = fixedPriorityListeners->size();            for (; i < size; ++i)            {                auto l = fixedPriorityListeners->at(i);                                if (l->isEnabled() && !l->isPaused() && l->isRegistered() && onEvent(l))                {                    shouldStopPropagation = true;                    break;                }            }        }    }}